Two-column Differential Pressure Distillation
Process description of two-column differential pressure distillation
The differential pressure of the process unit is: the differential pressure between rectifying column T502 and beer stripping column (mash column) T501.
1、The fermentation mash from fermentation section is preheated to 70 ℃ through primary preheater E502 (Fermentation mash is preheated by crude alcohol vapor that is condensed at the top of the mash column), secondary preheater E507 (Fermentation mash is double preheated by waste distillers in mash column), and feed into the mash column at the 24th tray. Fermentation mash is heated by the bottom steam when downward in the mash column T501, alcohol vapor is upward and separated from the waste mash. Waste mash is discharged at the bottom of the column, and the alcohol content of waste mash is no more than 0.05% and transported to the environmental protection section. Upward crude alcohol is for defoaming (low concentration alcohol) by 25th, 26th defoaming plates and enters into 1 # preheater, part of the alcohol vapor is condensed, uncooled alcohol vapor continues to be condensed by a set of condenser. The condensate liquid is heated indirectly by steam condensate water and residual distilling water (waste water at the bottom of the column) of rectifying column and enters into the rectifying column. Part of the crude alcohol refluxes (the purpose is for defoaming the crude alcohol gas), while some non-condensing gas is discharged into the atmosphere through the vacuum pump.
Heating mode of mash column: the alcohol vapor at the top of the rectifying column heats the mash column through the reboiler E501, The reboiler uses a circulating pump for circulation. The mash column works under the negative pressure, the negative pressure is produced by the connection of the vacuum pump through the condenser group.
2、Light alcohol from mash column T501 is indirectly heated by the steam condensate water, residual distilling water of rectifying column, enters into the rectifying column at the 18th tray. While the light alcohol is gradually concentrated, head impurities such as methanol and aldehyde are upward with alcohol vapor to the top of the column, part of impurities (such as oil) is retained on the upper layers of the feed plate whereby as fusel oil produced into the fusel oil separator for oil and alcohol separation. Fusel oil enters into fusel oil storage tank V509, and light alcohol enters into light alcohol tank and is pumped to the fermentation mash tank. The head impurities can be removed by extracted part of the reflux as industrial alcohol. The alcohol with a concentration of 95-96% (v/v) in the 6-8 trays below the reflux mouth of the column top is extracted as the finished product, and after cooling, the high concentration alcohol enters into the finished product alcohol tank.
Heating mode of rectifying column is heated indirectly by fresh steam through the rectifying column reboiler, and the condensate water is flash steamed and sent to the crude alcohol preheater by the condensate pump for exchanging heat with the crude alcohol and then return to the boiler room for reuse. The flash steam is used as part of the heat source of the beer stripping column.
|Column plate||Distillation column manufacture|
|Two-columns distillation||Three-columns distillation|
|Five-columns distillation||Several-columns distillation|